State Sen. Gilbert Baker, a former music professor, has created a grass-roots base from the anti-establishment side. Former state Sen. Jim Holt, who ran for Senate against Lincoln in 2006 and garnered 44 percent, is also considered a formidable candidate.

Recent polls show five Republican candidates beating Lincoln or Halter in a November match-up.

Outside interest is high

Lincoln and Halter have battered each other during the primary with television ads and mailers, especially about outsourcing jobs.